The broad goal in this research is to utilize the findings of tumor immunology in the development of tests for the detection of human cancer. Aspects of this research will include: 1. The identification of common tumor antigens. 2. The definition of the chemical nature of the antigenic substance. 3. The preparation of antisera of high affinity and specificity. 4. The development of sensitive test procedures to detect human cancer. Initial attention is being given to the carcinoembryonic antigen (CEA) in adenocarcinomas of intestinal, hepatic, and pancreatic tissue.